Invalid argument warning with Fusion and LightFantastic

I'm getting this warning on the LightFantastic settings page (admin/build/themes/settings/lightfantastic):
warning: Invalid argument supplied for foreach() in /sites/all/themes/fusion/fusion_core/theme-settings.php on line 129.

A similar problem is described here #691026: How do I remove the theme settings from a theme that used fusion before? with a custom Fusion-based theme. The suggestion in that thread did not work for me. Also I wasn't using any Fusion theme before I downloaded and Installed Fusion (1.0-rc1), LightFantastic (2.x-dev 2009-Oct-15) and SkinR (6.x-1.5). For the Abstract theme there's another such issue #767300: warning: Invalid argument supplied for foreach() in /.../themes/fusion/fusion_core/theme-settings.php on line 129.. Posting this here because I'm guessing the cause isn't in Fusion Core.

Any ideas where this comes from?